Process for mixing pulverulent materials



Feb; 13, 1923.

, 1,445,488. G. II. CLARK.

lPROCESS FOR MIXING PULVERULENT MATERIALS. AFILED 1AN.27, 1919.

I l I 4 I I "I M :I- I LII :Il 'l. A H 2 j l I4 P. 3 3 -f d f L Is Il I Ik .it

GEORGEJ. J. CLARK, 0F "VEST HNOVER, TEASSACHUSETTS, ASSIGNOR IO THE `NATIONAL' FIRETJOBKS ANUFACTUBING COJNHFANY, 03F WEST HANOVER,

MASSACHUSETTS,A CORPORATION OF ARIZONA.

PROCESS FOR MIXING PULVEBULENT MATERIALS.

` Application filed January 27, 1919. SerialNo. 273,282.

To all whom t may concern.'

. Be it known that l, Geenen J. J. CLARK,

a citizen ofthe United States, residingatv Vest Hanover, county of Plymouth, State of Massachusetts, have invented an improve-v ment' in Processes for Mixing Pulverulent Materials, of vvhichthe following description, in connection Withthe accompanying dra-Wing, isa specification, like characters y out causing` the `ingredientsto be pulverized.

More specifically the invention relates to improvements in processes and apparatus tor mixing granular chemicals, such as are used 4in pyrotechnical`devi-ces in Which a thorough mixture of the ingredients in predetermined ,proportions is necessary.

Inmixing" the composition used in vthe lmanufacture ot various ,y pyro-technical devices, it hasJ heretofore been, and now is the usual custom to introduce the various `ingredients in vthe predetermined proportions into a large receptacle fand to stir the ingredients by means of'a paddle manipulated by handuntil a homogeneous mixture is 0btained. kThe mixture then isrammed `into the Adesired container to form the pyro-technical device. A number fof pyro-technical devices made from each batch of composition are tested in order to determine Whether a proper mixture has been obtained and it' it is `found that the devices thus tested are defective, the `entire batch is discarded. It

is therefore very essential. in mixing' pj Totechnical substances, `that -a homogeneous mixture is obtained and that the ingredients oi" which the mixture is composed are of proper proportions to produce the desired eiectM" 1 1 Heretofore it has been very difficult to maintainl the properjproportions in each batch. ,andto make" different batches of uni- I :form 'quality sin ce fvari ons circumstances occurfduring the mixing operation `WhichA ,likely to cause avaria-tion in the produca For example, in mixing batches by hand, fine powders of the lighter materials arise and drift ofi" in the form of dust as the operator stirsthe mixture and of course the amounts of such ingredients are thereby I lessened, thus vitally affecting the mixture. Again, it is found that the condition of the humidity of the atmosphere affects the character ofthe mixture so that when the atmosphere is moist, a' greater proportion of certain ingredients is required than when the atmosphere is comparatively dry.

Many of the chemicals `which are used lin the manufacture of pyro-technical devices are of a poisonous character and consequently injurious to the health of the operator and various means have been devised to preventthe dust rising. during the mixing `operation frombeing inhaled by the operator; f y

One oi? the principal objects of the invention is to provide' a process `and apparatus 'for mixinggranular chemicals of this character which will prevent the loss of any of the ingredients which will prevent `the deleterious action of the moisture of the :itinosphere Aupon the chemicals and which 7will insure the operator from the effect of the poisonous materials which are being mixed.

provide a process and apparatus for mixing ingredients oi this character in which uniformity of the product will be insured so long as the chemicals are taken from the saine supplies, lthus avoiding the necessity ofmalrinp: so many tests.

Other objects and features of the invention will more fully appear from the following; description and the accompanying drawings andivill be pointed out in the annexed claims. y Y

The process of mixing pulverulent or granular 'rnaterials` or more `specifically chemicals, of the character above described, consists in introducing the ingredients to be mixed -in the predetermined proportions into substantially cylindrical receptacle,

closingsaid receptacleito prevent theescape of anymaterial thus introduced and rotatiinixed, the receptacles are desirably pro- ,able means.

ing` the receptacle about a horizontal or subl stantially horizontal axis until the materials tively small diameter and capacity so that I the weight of the materials and the friction of the particles against each other will be so small as not to pulverize any of the ingredients to a finer degree, since pulverization of' chemicals used Vin pyroftechnics affects the japidity of the combination with other ingredients during, the combustion of 'the' inixture. lfjtlieingredients of certain mixtures are coarsely granular the combustion isinuch sloiver than if the ingredients are finely4 granulated. It istherefore very iinportant that the predetermined granular Vcondition of the ingredients forming the "mixture shall be maintained.

ln order to prevent deleterious actionA of the atmosphere uponthe materials being vided with closures 4which may be hermeti- Vcally sealed so that the ingredients of the mixture are only subjected to the small 4amount of atmosphere which is present in the receptacles during their rotation. vrlhus the operator is enabled to introduce ern actly the right proportions of the various ingredients to produce the desired result Without fear that thecoinposition `will be affectedby changing of differing conditions in the atmosphere during the operation of inifi'ing one batch or of a number ofvbatches.

ln 'mixing compositions ot' the character above described, it isdesirable to have the composition at all times under the observaf. tion Vof the operator. A further object of the invention is to provide a process and ap-v paratus in which the ingredients shall be Amixed Within aclosed receptacle having a transparent Wall through Awhich the ininture `can always be seen. This is accomplished by the present invention by providfing a receptacle having a transparent wall, Vsuchas a glass Jar, provided with a siiitable closure., preferably hermetically sealing top.y and rotating the receptacleby snit- The process therefore of mirgranular materials may be said to coin- `prise-f 1 Y irst: introducing materials into a cyliiidrical, rotatable receptacle, closing the receptacle toprevent the escape of any of the vmaterial and `rota-ting the saine; i/,Secondz introducing the ingredients of lthe iiiaterial in a receptacle of the character specii'ied havinga closure which is adaptedlto he hermetically sealed; and

i Thirol: confining the ingredients vvhich are to form the composition in a rotatable i/ifiaeea Fig. l is a plan view of ainechanisni for i supporting and rotating the receptacles containing the ingredients to be mined.

Fig; 2 is a plan View Aupon a larger ,scale of a portion of said apparatus showing the mixing cylinders `in operative position; and

Fig. 3 is a vertical transverse lsectional view on lines 34-3 F ig. 2.

rlhe apparatus illustrated in the drawing is" adapted to rotate simultaneously 'a nurnber of mixturefcontaining receptacles.. lt

comprisesa rectangular fraine having sides l, 2 and ends `3, 4 and desrably a crosspiece` 5 connected to the vsides l, 2 interinediateof said `ends and preferably at the middle of the sides. shaft 6 having` a driving pulley `T is journaled in suitable bearings in the ends 3-4; and the cross-piece 5. The rollers 8, 9 are `suitably secured to the shaft 6 intermediate of the end 3 and the cross-piece 5 and between the crosspiece 5 and end l respectively These rollers de- `siralilyV are provided with parallel'surfaces "of frictional. preferably resilient;" niatciial voigreater or less extent, as inlay be desired.

iis illustrated herein bands lOof rubber or other resilientfniaterial are suitably secured to the rollers at intervals, or the entire surface of the rollerf and may if desired be covered with a suitablematerial which will engage frictionally the Wall of the receptacle to be rotated. v.Co-operating rollers ll, l2 are mounted respectively in suitable joui nals in the end and cross-piece 5; and the cross-piece 5 and end 4, and liein parallel'- isiii With the Vrollers 8 The pairs of rollers 8; 1l and `9, l2 are spaced apart to such a distance that the receptacles 13 will be` suitably supported by said rollers and rotated by frictional contact with thedriven rollers 8 and 9. rIhe roll-v and and may support other receptacles so that a number ofsuch receptacles may be rotated at the Sametime. 0f course as `many vof these rollers may be positively V.driven as desired Min steadof being driven from the Vrollers 8 and 9 as 'above described;

and 9 respectively.`

naa-snee The receptacles 13 preferably are of eylindrical form and constructed ogt glass or other transparent material. Any suitable closures may be provided tor the receptacles, Convenient closure being in the torin oi a screw cap 2l. such as is used ou ordinary glass preserving; runs. iis a. mattei' ot fact, the usual preserving cans may he eniployed tor the purposes above specified ln the operation of the machine, the various ingredients which are to torni the composition are weighed or measured out in predetermined proportions and placedl Within the receptacle 13, care being taken that the receptacle shall not be completely filled so that there will be snilicient room for the material to tumble about Within. the receptaole. The cap 2l is then screwed down upon the receptacle, a gasket 22 desire-bly being imposed between the cap and receptacle in order to hermetically seal the same.

rlhe receptacle, or as many receptacles as desired, may then be laid upon the rollers as indicated in Fig. 2 whereupon power applied to the pulley 7 will rotate the-receptacles in the manner above specified. The rotation may be continued until the miningr operation is complete and the ingredients commingled into a. homogeneous mass`r the condition of' the mixture being observed through the transparent. walls et the reeeptacle. ln order to prevent the receptacles traveling oil' the rollerl` bars 22-L3 may be "tas 'tened across the ends of the trame or between the side pieces 1 2 at such points as Will retain the receptacles in proper positions upon the rollers.

lt will be understood that various modi-- tications in the 'Form of apparatus may be made and that any means may be employed to rotate one or more receptacles Within the spirit and scope of the Claims which -follow.

Having thus described my invention what l claim new and desire to secure by Letters latent is:

l. rl`he method of uniformly mixing the pulverulent ingredient-s ot pyrotechnie devicesT which consists in aceumulating said pulverulent ingredients in predetermined proportions in a dry state in a contined substantially horizontal mass, an'itating, and .treely intermingling and inovirng` said ingredients about a horizontal axis of rota tion`l` and maintaining said confined mass of ingredients tree from exterior disturbing in* Jluences While being` thus agitated, intermingled and moved.

2. The method of uniformly mixing the anlverulent ingredients of pyrotechnic devices, which consists in accumulatingv the pulverulent ingredients in predetermined proportions in a dry state in a sealed and confined substantially horizontal massH :igitatingr. and freely interininglinnl and moving! said ingredients abont a horizontal axis' ot rotation and inspecting said Confined mass while sealed and confined.

in testimony Whereon l have signed my naine to this sgecitication. Y

GEORGE J. .l1 CLARK.. 

